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.\" ========================================================================
.\"
.IX Title "CPAN::Meta::Converter 3"
.TH CPAN::Meta::Converter 3 "2016-08-18" "perl v5.16.3" "User Contributed Perl Documentation"
.\" For nroff, turn off justification.  Always turn off hyphenation; it makes
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.SH "NAME"
CPAN::Meta::Converter \- Convert CPAN distribution metadata structures
.SH "VERSION"
.IX Header "VERSION"
version 2.150010
.SH "SYNOPSIS"
.IX Header "SYNOPSIS"
.Vb 1
\&  my $struct = decode_json_file(\*(AqMETA.json\*(Aq);
\&
\&  my $cmc = CPAN::Meta::Converter\->new( $struct );
\&
\&  my $new_struct = $cmc\->convert( version => "2" );
.Ve
.SH "DESCRIPTION"
.IX Header "DESCRIPTION"
This module converts \s-1CPAN\s0 Meta structures from one form to another.  The
primary use is to convert older structures to the most modern version of
the specification, but other transformations may be implemented in the
future as needed.  (E.g. stripping all custom fields or stripping all
optional fields.)
.SH "METHODS"
.IX Header "METHODS"
.SS "new"
.IX Subsection "new"
.Vb 1
\&  my $cmc = CPAN::Meta::Converter\->new( $struct );
.Ve
.PP
The constructor should be passed a valid metadata structure but invalid
structures are accepted.  If no meta-spec version is provided, version 1.0 will
be assumed.
.PP
Optionally, you can provide a \f(CW\*(C`default_version\*(C'\fR argument after \f(CW$struct\fR:
.PP
.Vb 1
\&  my $cmc = CPAN::Meta::Converter\->new( $struct, default_version => "1.4" );
.Ve
.PP
This is only needed when converting a metadata fragment that does not include a
\&\f(CW\*(C`meta\-spec\*(C'\fR field.
.SS "convert"
.IX Subsection "convert"
.Vb 1
\&  my $new_struct = $cmc\->convert( version => "2" );
.Ve
.PP
Returns a new hash reference with the metadata converted to a different form.
\&\f(CW\*(C`convert\*(C'\fR will die if any conversion/standardization still results in an
invalid structure.
.PP
Valid parameters include:
.IP "\(bu" 4
\&\f(CW\*(C`version\*(C'\fR \*(-- Indicates the desired specification version (e.g. \*(L"1.0\*(R", \*(L"1.1\*(R" ... \*(L"1.4\*(R", \*(L"2\*(R").
Defaults to the latest version of the \s-1CPAN\s0 Meta Spec.
.PP
Conversion proceeds through each version in turn.  For example, a version 1.2
structure might be converted to 1.3 then 1.4 then finally to version 2. The
conversion process attempts to clean-up simple errors and standardize data.
For example, if \f(CW\*(C`author\*(C'\fR is given as a scalar, it will converted to an array
reference containing the item. (Converting a structure to its own version will
also clean-up and standardize.)
.PP
When data are cleaned and standardized, missing or invalid fields will be
replaced with sensible defaults when possible.  This may be lossy or imprecise.
For example, some badly structured \s-1META\s0.yml files on \s-1CPAN\s0 have prerequisite
modules listed as both keys and values:
.PP
.Vb 1
\&  requires => { \*(AqFoo::Bar\*(Aq => \*(AqBam::Baz\*(Aq }
.Ve
.PP
These would be split and each converted to a prerequisite with a minimum
version of zero.
.PP
When some mandatory fields are missing or invalid, the conversion will attempt
to provide a sensible default or will fill them with a value of 'unknown'.  For
example a missing or unrecognized \f(CW\*(C`license\*(C'\fR field will result in a \f(CW\*(C`license\*(C'\fR
field of 'unknown'.  Fields that may get an 'unknown' include:
.IP "\(bu" 4
abstract
.IP "\(bu" 4
author
.IP "\(bu" 4
license
.SS "upgrade_fragment"
.IX Subsection "upgrade_fragment"
.Vb 1
\&  my $new_struct = $cmc\->upgrade_fragment;
.Ve
.PP
Returns a new hash reference with the metadata converted to the latest version
of the \s-1CPAN\s0 Meta Spec.  No validation is done on the result \*(-- you must
validate after merging fragments into a complete metadata document.
.PP
Available since version 2.141170.
.SH "BUGS"
.IX Header "BUGS"
Please report any bugs or feature using the \s-1CPAN\s0 Request Tracker.
Bugs can be submitted through the web interface at
<http://rt.cpan.org/Dist/Display.html?Queue=CPAN\-Meta>
.PP
When submitting a bug or request, please include a test-file or a patch to an
existing test-file that illustrates the bug or desired feature.
.SH "AUTHORS"
.IX Header "AUTHORS"
.IP "\(bu" 4
David Golden <dagolden@cpan.org>
.IP "\(bu" 4
Ricardo Signes <rjbs@cpan.org>
.IP "\(bu" 4
Adam Kennedy <adamk@cpan.org>
.SH "COPYRIGHT AND LICENSE"
.IX Header "COPYRIGHT AND LICENSE"
This software is copyright (c) 2010 by David Golden, Ricardo Signes, Adam Kennedy and Contributors.
.PP
This is free software; you can redistribute it and/or modify it under
the same terms as the Perl 5 programming language system itself.